LUFKIN, Texas (AP) – Kimberly Saenz worked eight months as a nurse at the busiest dialysis clinic in town. Her turbulent final month on the job is all anyone remembers.

One patient after another died last April for reasons no one could explain. Ambulances had to rush people to the emergency room almost every day. Things got so grim at the Lufkin Dialysis Center that the clinic shut down to investigate.

One year later, prosecutors say they have an explanation: Saenz deliberately injected 10 patients with bleach, killing five of them in what were probably excruciatingly painful deaths.

Investigators have offered no hint at a motive.

“How can someone that sick walk around and appear to be a normal person?” said Linda Few, whose mother, Opal, was among the five who died. “This many people? It’s blowing my mind. I mean, we live in Lufkin.”

In a chilling indictment handed up this week, Saenz, 35, was charged with one count of capital murder covering five patients. She was also charged with aggravated assault against five other patients who were allegedly injected with bleach but survived.

Among them was Debra Oates, who left the clinic on an ambulance stretcher April 26 last year when her arm would not stop bleeding. Her nurse that day was Saenz, who Oates said often helped her pass the dreary, hours-long dialysis treatments by telling jokes.

“I started throwing up and having chest pains,” Oates said last year. “I was hurting all over.”

Oates said she watched three people before her rushed to the hospital on the same day she was stricken. Altogether, 34 emergency calls were made from the clinic in April – more than three times the number in March.

Investigators believe Saenz used syringes to inject bleach into the patients’ dialysis lines.

Authorities first charged Saenz last May with two counts of aggravated assault after two witnesses said they saw her draw bleach into syringes.

, and traces of bleach were found in the dialysis machine tubing. Both of those patients lived.

After being charged with murder, Saenz turned herself in Wednesday and was jailed without bail. Neither her lawyer nor family members returned calls for comment.

Dialysis is a mostly miserable routine for about 325,000 people nationwide with kidney failure. Most spend three days a week tethered for hours to a machine that filters their blood – a job their kidneys can no longer do.

Bleach is a staple at dialysis centers, where it is used to clean the tubing and machines between patients. When injected into the blood, even a small amount can be lethal.

Bleach destroys tissue and causes red blood cells to burst, releasing a toxic overload of potassium that can cause cardiac arrest, with heart attack-like chest pain, said Dr. Kurt Kleinschmidt, who runs the toxicology section at the UT Southwestern Medical Center in Dallas.

He said that bleach is eliminated from the body fairly quickly and that those who survived probably suffered no lasting effects.

The clinic in Lufkin, a blue-collar city of about 33,000 in the piney woods of East Texas, is run by El Segundo, Calif.-based DaVita Inc., which controls a large share of the dialysis market with more than 1,300 centers.

DaVita fired Saenz a day after closing the Lufkin clinic on April 28. Some families fault DaVita for not acting more quickly – two of the deaths occurred April 1 – but the company said Saenz would not have been caught if the clinic had shut down sooner. The place has since reopened.

Among Saenz’s alleged victims was Thelma Metcalf, who died while hooked up to a dialysis machine April 1. Saenz’s name appears that day on Metcalf’s paperwork, and the number 29, denoting cardiac arrest, is listed as the cause of death.

“I just can’t see anyone getting away with this without anyone noticing this was going on,” Wanda Hollingsworth, Metcalf’s daughter, said last year.

AP-ES-04-02-09 1708EDT

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